Rubber-reinforced vinyl-based resins such as typically ABS resins have been extensively used in various applications such as vehicles, domestic appliances and building materials because of excellent coatability, impact resistance and moldability thereof. Among these applications, the rubber-reinforced vinyl-based resins have been frequently employed in the application field of vehicles in which the resins tend to be often subjected to coating treatment for imparting decorations thereto or improving a weather resistance thereof. However, these coated molded products may fail to have a good coating appearance, for example, owing to the problems concerning chemical resistance to thinners, coating adhesion property, etc.
As large-size coated molded products, there are known spoilers obtained by a blow-molding method (Patent Document 1). However, the blow-molding method tends to have a low productivity as compared to an injection-molding method, and also tend to suffer from problems such as limited degree of freedom of designing a shape of the molded products. On the other hand, the injection-molding method tends to suffer from coating defects owing to residual strain on a surface of the molded products, in particular, the large-size molded products tend to more remarkably suffer from such coating defects.
To solve the above conventional problems, there have been described various resin compositions comprising rubber-reinforced vinyl-based resins such as typically ABS resins which are improved in chemical resistance thereof, for example, there have been proposed thermoplastic resins comprising a rubber-reinforced styrene-based resin and a terpolymer of ethylene, a (meth)acrylic acid ester and carbon dioxide (Patent Document 1).
On the other hand, as the resin composition using a polyester resin having excellent mechanical strength and chemical resistance, there have been proposed thermoplastic resins comprising an ABS resin, a polyester resin and a terpolymer of ethylene, a (meth)acrylic acid ester and carbon dioxide (Patent Document 2).
However, the rubber-reinforced vinyl-based resins such as typically ABS resins tend to be insufficient in chemical resistance to organic solvents such as thinners although they are excellent in adhesion between the resins and coating films. For this reason, the rubber-reinforced vinyl-based resins tend to absorb the organic solvents such as thinners therein, so that the resins after coated tend to frequently suffer from coating defects such as so-called foaming on a surface of the coating film owing to the organic solvent volatilized in the resin after coating (depressions formed by volatilization of the organic solvent absorbed in the resins). On the other hand, the polyester resins exhibit an excellent chemical resistance to organic solvents such as thinners, but tend to be deteriorated in adhesion between the resins and coating films and therefore tends to be deteriorated in impact resistance owing to hydrolysis thereof when exposed to high temperatures. In addition, the rubber-reinforced styrene-based resins in the form of a non-crystalline resin and the polyester resins in the form of a crystalline resin tend to have a poor compatibility therebetween, and therefore tend to be limited in their applications when used in the form of a mixture thereof.
Accordingly, the above conventionally proposed respective compositions tend to fail to exhibit a sufficient balance between heat resistance, impact resistance, chemical resistance and coatability and therefore tend to be limited in applications when used as a coated product.